The present invention relates to methods and installations which make it possible to produce assemblies of textile threads.
The expression "thread" is to be understood in a very broad sense. A thread may be a "single thread" formed of one or more filaments. When the single thread is formed of a single filament, it is referred to as a "monofilament" and when the single thread is formed of several filaments, it is called a "multifilament". A thread may, furthermore, itself be an assembly of single threads.
An assembly of threads is referred to as a "plied yarn" when it is formed of a plurality of single threads twisted together by a single twist and an assembly of threads is referred to as a "cabled yarn" when it is formed of several threads at least one of which is a plied yarn which are combined together by one or more twists.
Such assemblies are used, for instance, in order to reinforce articles of plastic and/or rubber, such articles being, for instance, belts, hoses and tires.
One known method for the manufacture of textile assemblies comprises several successive operations, which can be divided into two main families:
the operations of assembling textile threads; these operations can be carried out in one step with, for instance, a direct cabling method or in several steps, for instance, by first of all preparing twisted multifilaments which are then assembled in order to obtain plied yarns; the assemblies are thus obtained in the form of bobbins; PA1 a warping operation, by unwinding a number of bobbins of assemblies in order to wind them on a beam. PA1 the operations are complicated and expensive, and they lack flexibility; PA1 it is practically impossible to have a large number of bobbins which have the same length; it is, therefore, necessary to effect knots or attachments upon the winding on the beam, which takes time and results in the formation of defects, or else no attachment is effected, but then there is a large amount of waste; PA1 the length of the assemblies varies on one in the same beam since it is practically impossible to deliver the same length from each bobbin. PA1 a) a plurality of rotary devices is used, each of which permits the production of an assembly from a plurality of threads so as to obtain a ply of assemblies; PA1 b) the assemblies are produced in such a manner that in transitory operation, that is to say, when the speed of rotation of each device varies in time between a value of zero and an arbitrary value corresponding to continuous operation, one has the relationship ##EQU1## L1 being the length of the longest thread of the assembly and L2 being the length of the shortest thread of the assembly, L1 and L2 being determined for the arbitrary length L of the assembly produced by this device, and .epsilon. being an arbitrary value; PA1 c) the ply of assemblies is driven along by pulling means common to all the assemblies; PA1 d) means are used which, on the one hand, make it possible to synchronize the speeds of rotation of the devices with each other so as to have a common speed for these devices and, on the other hand, to synchronize the speed of the devices and the speed of the pulling means; PA1 e) the ply of assemblies is wound on the beam; PA1 f) means are used which make it possible to detect a possible defect on at least any one thread or at least any one assembly; PA1 g) the production of the ply and the winding of the ply on the beam are interrupted when such a defect is detected, this interruption being effected in such a manner that, upon the interruption, the defect is located in front of the beam in the ply, seen in the direction of advance of the ply. PA1 a) it comprises a plurality of rotary devices, each of which permits the production of an assembly from a plurality of threads so as to obtain a ply of assemblies; PA1 b) each device is such that in transitory operation, that is to say, when the speed of rotation of this device varies in time between a value of zero and an arbitrary value corresponding to continuous operation of the installation, one has the relationship ##EQU2## L1 being the length of the longest thread of the assembly and L2 being the length of the shortest thread of the assembly, L1 and L2 being determined for the arbitrary length L of the assembly produced by this device, and .epsilon. being an arbitrary value; PA1 c) it comprises pulling means common to all the assemblies, permitting the driving of the ply of assemblies; PA1 d) it comprises means which, on the one hand, make it possible to synchronize the speeds of rotation of the devices with each other so as to have a common speed for these devices and, on the other hand, to synchronize the speed of the devices and the speed of the pulling means; PA1 e) it comprises a beam and means making it possible to wind the ply of assemblies on the beam; PA1 f) it comprises means which make it possible to detect a possible defect on at least any one thread or at least any one assembly; PA1 g) it comprises means making it possible to shut down the installation when such a defect is detected, the installation being so arranged that when the installation is thus shut down, the defect is located in front of the beam in the ply, as seen in the direction of advance of the ply.
This method has the following drawbacks:
It has been attempted to produce a ply of an assembly of threads and the winding of said ply on a beam on line but up to now this has been very difficult in practice since the defects coming from the threads or assemblies lead to the frequent stopping of the installation and the repair of these defects and the stopping and restarting of the installations lead to extensive waste, a decrease in the quality of the assemblies, and high costs and long periods of stoppage.